It's hard to explain Sleep No More, the immersive theater experience unfolding in a hotel-styled warehouse in West Chelsea, in just a few words. "Macbeth in a hotel" (thanks, New York Times) does a pretty good job of it. The British theater company Punchdrunk enacts the approximate arc of the Scottish play over a huge, sprawling complex dubbed the McKittrick Hotel, as mask-wearing audience members follow the characters, explore the space, and get pretty amazingly disoriented.

But where do you go on West 27th, after (or before) wandering the halls of the McKittrick? Gallow Green, they're hoping, the rooftop bar they "officially" opened last week (but was open "in previews" a bit before that).

The space itself is the first draw—with artfully overgrown greenery and a precisely worn-down feel, it has the sense of a place just stumbled upon, a bar they found rather than created. While this isn't the case, of course, the team did find more than they expected atop the space they used to create the McKittrick Hotel: an unkempt expanse of roof with—really—train tracks running down the middle. True to theme, there's a gracefully decaying trolley car on the other side of the space—no, that wasn't here along with it. Waiters glide around in white uniforms, lights twinkle overhead, the music kicks up as the night goes on.

But the drinks themselves are the second draw, from legendary cocktailian Dave Wondrich, brought in to design the drink menu. Initially working with Sleep No More on a single Bowmore Scotch event held at the McKittrick, as part of the Manhattan Cocktail Classic, Wondrich's Scotch punches worked so well that the team brought him on for a permanent project. "We worked with them to do something really unique, something that captured the spirit of all this."

Cocktails are certainly named in that fashion, dubbed the Blonde in Peril or the Damned Spot (with a creeping red float of Peychaud's bitters). The punches, Wondrich's real specialty, add a further element of theatricality: poured out into tureens tableside, some warm with Scotch, some indulgent with a whole bottle of Champagne—and some with jumping flames of absinthe alit.